A. Field of the Invention
This invention relates generally to carpet stretching tools for use during laying of carpets.
B. Description of the Related Art
During the installation of wall-to-wall carpet, an installer typically first secures tacking boards on the floor adjacent to the walls of the room. The installer secures an end of the carpet to the tacking boards located on one side of the room. Then, the installer uses a carpet stretching tool to stretch the carpet prior to securing the other end of the carpet to the tacking boards on the opposite side of the room. Stretching the carpet in this way reduces or eliminates wrinkling in the carpet.
A conventional carpet stretching tool is known as the "knee kicker." It has a gripping head at one end furnished with prongs or teeth for engaging and gripping into the carpet, and a padded kicker plate at the other end. An elongate shank typically interconnects the gripping head and kicker plate. The shank often has telescoping elements, e.g., an inner tube connected to the kicker plate and an outer tube connected to the gripping head. The tubes are mounted for translation, one within the other, so as to permit the length of the shank to be continuously adjustable during set up of the tool.
During use of the conventional knee kicker, the installer first sets up the tool by adjusting the length of the shank of the tool, and then actuating a lock mechanism to interlock the shank's tubes to prevent their relative motion. Afterwards, during use, the installer bumps or strikes the kicker plate with his knee. This action causes the tube attached to the kicker plate to impact a stop or strike plate in the outer tube with sufficient momentum to thrust the gripping head forward, thereby stretching the carpet.
While knee kickers are generally suitable for their intended purpose and are widely used, they do have certain drawbacks. For example, it is difficult to use knee kickers effectively in tight spaces, such as in hallways or stairs. Such spaces often do not provide sufficient room for the installer to place his knee in a "kicking" position behind the padded kicker plate.
Moreover, experience has shown that prolonged use of the knee kicker can cause injury to the knee; the knee is not meant to be used as a hammer. Professional carpet installers can suffer not only painful bruises resulting from using the knee kicker, but, over time, can even develop permanent knee trouble or disability. This can prove expensive for carpet installation companies that have to pay workers compensation for such injuries. Inexperienced carpet installers, such as "do-it-yourselfers", may be even more prone to injury, according to reports from stores that rent knee kickers.
These drawbacks with knee kickers have been recognized heretofore. U.S. Pat. No. 3,940,170 proposed a modified knee kicker that has a kick plate connected by a rigid shank to a gripping head, and also has a so-called "hand weight" that can slide along the shank. That patent's carpet stretcher can be operated by striking the kicker plate with the knee. That patent's carpet stretcher can alternatively be operated by hand by propelling the hand weight from a position along the shank adjacent the kicker plate to a position adjacent the gripping head at which the hand weight strikes a stop in hammer-like fashion. Unfortunately, the limited free travel or "throw" of the hand weight along the shank prevents the hand weight from developing much momentum before it strikes the stop. Thus, hand operation of that carpet stretcher would not be particularly effective at stretching carpet.
Another conventional type of carpet stretcher employs a tail block or butt plate in addition to a carpet gripping head. The installer positions the tail block against a wall of the room, and hand operates a toggle-type mechanism near the gripping head to drive the gripping head away from the tail block. While such a carpet stretcher avoids the necessity of using the installer's knee as a hammer, it can require considerable and time-consuming assembly and set up for use, in addition to fortuitously placed walls that are usable for this purpose.
Accordingly, it would be desirable to provide an efficient carpet stretching tool that is not actuated by the installer's knee, that can be used in tight spaces, and that does not require any significant set up or assembly for use.